Virginia state Sen. William Stanley (R-Franklin County) thinks the days of the Democratic ascendancy in Virginia are just about done, and the GOP is feeling good about itself again.

The Southside Republican told The Post’s Laura Vozzella there’s “a new spring in our step” and that Democrats are “scared” of what lies over the political horizon.

When that story went to press March 23, the Mueller report, a potential game-changer, was just over the horizon. (More specifically, the release of Attorney General William P. Barr’s summary of the Mueller report.)

Collusion fantasies were vanquished. Obstruction dreams dashed. The president may be deeply unfit for national office, but he’s not working arm-in-arm with the Kremlin to overthrow the republic.

And so the conspiracy-laden cloud hanging over the White House, and, by extension, the psyches of elected Republicans everywhere, is rapidly dissipating.

Make no mistake: This administration faces plenty of potential legal problems and will remain the object of congressional investigations.

But not because of special counsel Robert S. Mueller III.

On the national level, that means Democrats have to buckle down and do the hard work of fighting the president on the fundamentals: policy, personnel and personality. That’s hard and definitely less headline-friendly work.

It also means less coverage for Sen. Mark R. Warner (D-Va.), who should be too busy walking back recent statements to talk to the press.

But just because it’s boring doesn’t mean it’s impossible.

Virginia Democrats have been winning statewide races since 2009. They didn’t need Trump to sweep the top three state offices in 2013. Warner did his level best to lose in 2014 but managed to hang on despite himself in a strong Republican year. And the Democratic presidential ticket has carried the state in three consecutive elections.

The Trump overhang contributed to a wave election that nearly gave Democrats control of the House of Delegates in 2017 and played a powerful supporting role in the 2018 congressional midterms that saw three Republicans defeated.

But Mueller didn’t deliver what the Democratic resistance desperately needed heading into this November’s elections: fresh fuel in the outrage tank.

Democrats (and Republicans) know that outrage over the president helped them the past two elections.

Take away President Trump and put any other Republican (even Ted Cruz) or, say, 2016 Democratic presidential nominee Hillary Clinton in the White House, and this year’s elections look very different. Republicans likely still have a wide majority in the House of Delegates, and there’s been no Medicaid expansion because of it. And Ralph Northam? He runs in 2017 against an Ed Gillespie campaign that isn’t haunted by Trump. And Virginia Republicans are not saddled with Corey A. Stewart in 2017 or 2018.

But that’s the stuff of fan fiction — and it belongs on the shelf right next to the Mueller tales.

It doesn’t, however, diminish the difficulty Democrats have of sustaining the anti-Trump anger for a fourth consecutive election.

Had Mueller clapped rhetorical manacles on the president, it would have helped overcome the off-off year election fatigue.

And perhaps it would have been enough to make some voters forget the scandals around Northam, Lieutenant Governor Justin Fairfax and Attorney General Mark R. Herring, all Democrats.

Randolph Macon professor Lauren Bell told me that those scandals probably don’t matter nearly as much as Republicans hope.

Plus, Bell noted Republicans have to contend with issues entirely out of their hands, including a pending Supreme Court decision on whether a dozen of the state’s House districts were racially gerrymandered and 200,000 new voters on the state rolls since 2017.

Those are real headwinds.

But Stanley was onto something. Yes, the GOP does have a bit of a spring in its step.

Thanks to Mueller, it may last until Election Day.